Linear and sliding-mode controllers for three-phase four-wire power converters

This paper presents the voltage regulation system design for a three-phase four-wire voltage converter using linear and sliding-mode control techniques. The regulation systems proposed are applied to a four-leg voltage source converter connected to the ac mains. System modelling and controllers syntheses are realized and compared. Digital simulations highlight the voltage regulation characteristics in terms of steady-state and transient responses. The robustness to disturbances influence is also analysed. Conclusions are taken with respect to the different approaches presented and the type of application where the dc voltage regulation is needed, like active power filters, unified power flow controllers, neutral current compensators, PWM rectifiers and others.